Stability of malathion, diazinon and chlorpyrifos in different water types – a review

Prior to their application, most pesticide formulations should be mixed with water to form a spray of the required concentration. The efficiency of the active substance in the spray solutions could be affected by the quality of the used water, whose composition is related to its source (e.g., rain, river, stream, lake, tap and ground water) and sampling season (spring-autumn). Temperature and pH, as well as other water quality parameters, could significantly affect the pesticide stability in spray by promoting the pesticide degradation rate. This review aims to summarize and discuss degradation data of three widely used organophosphorus insecticides (malathion, diazinon and chlorpyrifos) in different types of water in order to emphasize the influence of different water types on their degradation. This review also reveals a lack of studies that can confirm the effect of other water quality parameters, except temperature and pH, on the stability of pesticides susceptible to hydrolysis.